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| author | Arnaud Charlet <charlet@gcc.gnu.org> | 2017-09-11 12:12:05 +0200 |
|---|---|---|
| committer | Arnaud Charlet <charlet@gcc.gnu.org> | 2017-09-11 12:12:05 +0200 |
| commit | a0713cb6beb00ca850e7c20f287d32f1e1a14a49 (patch) | |
| tree | c3c846308e8396ca48bd205ca87021e5afd9a0f0 /gcc/ada/libgnat/s-osprim__mingw.adb | |
| parent | 6f77df7260f6f1ce89ecb2ee82d9f40447d813bc (diff) | |
| download | gcc-a0713cb6beb00ca850e7c20f287d32f1e1a14a49.zip gcc-a0713cb6beb00ca850e7c20f287d32f1e1a14a49.tar.gz gcc-a0713cb6beb00ca850e7c20f287d32f1e1a14a49.tar.bz2 | |
libgnat: Rename ?-[a-z]*-* into ?-[a-z]*__*
2017-09-11 Jerome Lambourg <lambourg@adacore.com>
* libgnat: Rename ?-[a-z]*-* into ?-[a-z]*__*
* gcc-interface/Makefile.in, gcc-interface/Make-lang.in: Take this
renaming into account.
From-SVN: r251968
Diffstat (limited to 'gcc/ada/libgnat/s-osprim__mingw.adb')
| -rw-r--r-- | gcc/ada/libgnat/s-osprim__mingw.adb | 413 |
1 files changed, 413 insertions, 0 deletions
diff --git a/gcc/ada/libgnat/s-osprim__mingw.adb b/gcc/ada/libgnat/s-osprim__mingw.adb new file mode 100644 index 0000000..d729d85 --- /dev/null +++ b/gcc/ada/libgnat/s-osprim__mingw.adb @@ -0,0 +1,413 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- +-- -- +-- S Y S T E M . O S _ P R I M I T I V E S -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1998-2017, Free Software Foundation, Inc. -- +-- -- +-- GNARL is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 3, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. -- +-- -- +-- As a special exception under Section 7 of GPL version 3, you are granted -- +-- additional permissions described in the GCC Runtime Library Exception, -- +-- version 3.1, as published by the Free Software Foundation. -- +-- -- +-- You should have received a copy of the GNU General Public License and -- +-- a copy of the GCC Runtime Library Exception along with this program; -- +-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- +-- <http://www.gnu.org/licenses/>. -- +-- -- +-- GNARL was developed by the GNARL team at Florida State University. -- +-- Extensive contributions were provided by Ada Core Technologies, Inc. -- +-- -- +------------------------------------------------------------------------------ + +-- This is the NT version of this package + +with System.Task_Lock; +with System.Win32.Ext; + +package body System.OS_Primitives is + + use System.Task_Lock; + use System.Win32; + use System.Win32.Ext; + + ---------------------------------------- + -- Data for the high resolution clock -- + ---------------------------------------- + + Tick_Frequency : aliased LARGE_INTEGER; + -- Holds frequency of high-performance counter used by Clock + -- Windows NT uses a 1_193_182 Hz counter on PCs. + + Base_Monotonic_Ticks : LARGE_INTEGER; + -- Holds the Tick count for the base monotonic time + + Base_Monotonic_Clock : Duration; + -- Holds the current clock for monotonic clock's base time + + type Clock_Data is record + Base_Ticks : LARGE_INTEGER; + -- Holds the Tick count for the base time + + Base_Time : Long_Long_Integer; + -- Holds the base time used to check for system time change, used with + -- the standard clock. + + Base_Clock : Duration; + -- Holds the current clock for the standard clock's base time + end record; + + type Clock_Data_Access is access all Clock_Data; + + -- Two base clock buffers. This is used to be able to update a buffer while + -- the other buffer is read. The point is that we do not want to use a lock + -- inside the Clock routine for performance reasons. We still use a lock + -- in the Get_Base_Time which is called very rarely. Current is a pointer, + -- the pragma Atomic is there to ensure that the value can be set or read + -- atomically. That's it, when Get_Base_Time has updated a buffer the + -- switch to the new value is done by changing Current pointer. + + First, Second : aliased Clock_Data; + + Current : Clock_Data_Access := First'Access; + pragma Atomic (Current); + + -- The following signature is to detect change on the base clock data + -- above. The signature is a modular type, it will wrap around without + -- raising an exception. We would need to have exactly 2**32 updates of + -- the base data for the changes to get undetected. + + type Signature_Type is mod 2**32; + Signature : Signature_Type := 0; + pragma Atomic (Signature); + + function Monotonic_Clock return Duration; + pragma Export (Ada, Monotonic_Clock, "__gnat_monotonic_clock"); + -- Return "absolute" time, represented as an offset relative to "the Unix + -- Epoch", which is Jan 1, 1970 00:00:00 UTC. This clock implementation is + -- immune to the system's clock changes. Export this function so that it + -- can be imported from s-taprop-mingw.adb without changing the shared + -- spec (s-osprim.ads). + + procedure Get_Base_Time (Data : in out Clock_Data); + -- Retrieve the base time and base ticks. These values will be used by + -- clock to compute the current time by adding to it a fraction of the + -- performance counter. This is for the implementation of a high-resolution + -- clock. Note that this routine does not change the base monotonic values + -- used by the monotonic clock. + + ----------- + -- Clock -- + ----------- + + -- This implementation of clock provides high resolution timer values + -- using QueryPerformanceCounter. This call return a 64 bits values (based + -- on the 8253 16 bits counter). This counter is updated every 1/1_193_182 + -- times per seconds. The call to QueryPerformanceCounter takes 6 + -- microsecs to complete. + + function Clock return Duration is + Max_Shift : constant Duration := 2.0; + Hundreds_Nano_In_Sec : constant Long_Long_Float := 1.0E7; + Data : Clock_Data; + Current_Ticks : aliased LARGE_INTEGER; + Elap_Secs_Tick : Duration; + Elap_Secs_Sys : Duration; + Now : aliased Long_Long_Integer; + Sig1, Sig2 : Signature_Type; + + begin + -- Try ten times to get a coherent set of base data. For this we just + -- check that the signature hasn't changed during the copy of the + -- current data. + -- + -- This loop will always be done once if there is no interleaved call + -- to Get_Base_Time. + + for K in 1 .. 10 loop + Sig1 := Signature; + Data := Current.all; + Sig2 := Signature; + exit when Sig1 = Sig2; + end loop; + + if QueryPerformanceCounter (Current_Ticks'Access) = Win32.FALSE then + return 0.0; + end if; + + GetSystemTimeAsFileTime (Now'Access); + + Elap_Secs_Sys := + Duration (Long_Long_Float (abs (Now - Data.Base_Time)) / + Hundreds_Nano_In_Sec); + + Elap_Secs_Tick := + Duration (Long_Long_Float (Current_Ticks - Data.Base_Ticks) / + Long_Long_Float (Tick_Frequency)); + + -- If we have a shift of more than Max_Shift seconds we resynchronize + -- the Clock. This is probably due to a manual Clock adjustment, a DST + -- adjustment or an NTP synchronisation. And we want to adjust the time + -- for this system (non-monotonic) clock. + + if abs (Elap_Secs_Sys - Elap_Secs_Tick) > Max_Shift then + Get_Base_Time (Data); + + Elap_Secs_Tick := + Duration (Long_Long_Float (Current_Ticks - Data.Base_Ticks) / + Long_Long_Float (Tick_Frequency)); + end if; + + return Data.Base_Clock + Elap_Secs_Tick; + end Clock; + + ------------------- + -- Get_Base_Time -- + ------------------- + + procedure Get_Base_Time (Data : in out Clock_Data) is + + -- The resolution for GetSystemTime is 1 millisecond + + -- The time to get both base times should take less than 1 millisecond. + -- Therefore, the elapsed time reported by GetSystemTime between both + -- actions should be null. + + epoch_1970 : constant := 16#19D_B1DE_D53E_8000#; -- win32 UTC epoch + system_time_ns : constant := 100; -- 100 ns per tick + Sec_Unit : constant := 10#1#E9; + + Max_Elapsed : constant LARGE_INTEGER := + LARGE_INTEGER (Tick_Frequency / 100_000); + -- Look for a precision of 0.01 ms + + Sig : constant Signature_Type := Signature; + + Loc_Ticks, Ctrl_Ticks : aliased LARGE_INTEGER; + Loc_Time, Ctrl_Time : aliased Long_Long_Integer; + Elapsed : LARGE_INTEGER; + Current_Max : LARGE_INTEGER := LARGE_INTEGER'Last; + New_Data : Clock_Data_Access; + + begin + -- Here we must be sure that both of these calls are done in a short + -- amount of time. Both are base time and should in theory be taken + -- at the very same time. + + -- The goal of the following loop is to synchronize the system time + -- with the Win32 performance counter by getting a base offset for both. + -- Using these offsets it is then possible to compute actual time using + -- a performance counter which has a better precision than the Win32 + -- time API. + + -- Try at most 10 times to reach the best synchronisation (below 1 + -- millisecond) otherwise the runtime will use the best value reached + -- during the runs. + + Lock; + + -- First check that the current value has not been updated. This + -- could happen if another task has called Clock at the same time + -- and that Max_Shift has been reached too. + -- + -- But if the current value has been changed just before we entered + -- into the critical section, we can safely return as the current + -- base data (time, clock, ticks) have already been updated. + + if Sig /= Signature then + Unlock; + return; + end if; + + -- Check for the unused data buffer and set New_Data to point to it + + if Current = First'Access then + New_Data := Second'Access; + else + New_Data := First'Access; + end if; + + for K in 1 .. 10 loop + if QueryPerformanceCounter (Loc_Ticks'Access) = Win32.FALSE then + pragma Assert + (Standard.False, + "Could not query high performance counter in Clock"); + null; + end if; + + GetSystemTimeAsFileTime (Ctrl_Time'Access); + + -- Scan for clock tick, will take up to 16ms/1ms depending on PC. + -- This cannot be an infinite loop or the system hardware is badly + -- damaged. + + loop + GetSystemTimeAsFileTime (Loc_Time'Access); + + if QueryPerformanceCounter (Ctrl_Ticks'Access) = Win32.FALSE then + pragma Assert + (Standard.False, + "Could not query high performance counter in Clock"); + null; + end if; + + exit when Loc_Time /= Ctrl_Time; + Loc_Ticks := Ctrl_Ticks; + end loop; + + -- Check elapsed Performance Counter between samples + -- to choose the best one. + + Elapsed := Ctrl_Ticks - Loc_Ticks; + + if Elapsed < Current_Max then + New_Data.Base_Time := Loc_Time; + New_Data.Base_Ticks := Loc_Ticks; + Current_Max := Elapsed; + + -- Exit the loop when we have reached the expected precision + + exit when Elapsed <= Max_Elapsed; + end if; + end loop; + + New_Data.Base_Clock := + Duration + (Long_Long_Float + ((New_Data.Base_Time - epoch_1970) * system_time_ns) / + Long_Long_Float (Sec_Unit)); + + -- At this point all the base values have been set into the new data + -- record. Change the pointer (atomic operation) to these new values. + + Current := New_Data; + Data := New_Data.all; + + -- Set new signature for this data set + + Signature := Signature + 1; + + Unlock; + + exception + when others => + Unlock; + raise; + end Get_Base_Time; + + --------------------- + -- Monotonic_Clock -- + --------------------- + + function Monotonic_Clock return Duration is + Current_Ticks : aliased LARGE_INTEGER; + Elap_Secs_Tick : Duration; + + begin + if QueryPerformanceCounter (Current_Ticks'Access) = Win32.FALSE then + return 0.0; + + else + Elap_Secs_Tick := + Duration (Long_Long_Float (Current_Ticks - Base_Monotonic_Ticks) / + Long_Long_Float (Tick_Frequency)); + return Base_Monotonic_Clock + Elap_Secs_Tick; + end if; + end Monotonic_Clock; + + ----------------- + -- Timed_Delay -- + ----------------- + + procedure Timed_Delay (Time : Duration; Mode : Integer) is + function Mode_Clock return Duration; + pragma Inline (Mode_Clock); + -- Return the current clock value using either the monotonic clock or + -- standard clock depending on the Mode value. + + ---------------- + -- Mode_Clock -- + ---------------- + + function Mode_Clock return Duration is + begin + case Mode is + when Absolute_RT => return Monotonic_Clock; + when others => return Clock; + end case; + end Mode_Clock; + + -- Local Variables + + Base_Time : constant Duration := Mode_Clock; + -- Base_Time is used to detect clock set backward, in this case we + -- cannot ensure the delay accuracy. + + Rel_Time : Duration; + Abs_Time : Duration; + Check_Time : Duration := Base_Time; + + -- Start of processing for Timed Delay + + begin + if Mode = Relative then + Rel_Time := Time; + Abs_Time := Time + Check_Time; + else + Rel_Time := Time - Check_Time; + Abs_Time := Time; + end if; + + if Rel_Time > 0.0 then + loop + Sleep (DWORD (Rel_Time * 1000.0)); + Check_Time := Mode_Clock; + + exit when Abs_Time <= Check_Time or else Check_Time < Base_Time; + + Rel_Time := Abs_Time - Check_Time; + end loop; + end if; + end Timed_Delay; + + ---------------- + -- Initialize -- + ---------------- + + Initialized : Boolean := False; + + procedure Initialize is + begin + if Initialized then + return; + end if; + + Initialized := True; + + -- Get starting time as base + + if QueryPerformanceFrequency (Tick_Frequency'Access) = Win32.FALSE then + raise Program_Error with + "cannot get high performance counter frequency"; + end if; + + Get_Base_Time (Current.all); + + -- Keep base clock and ticks for the monotonic clock. These values + -- should never be changed to ensure proper behavior of the monotonic + -- clock. + + Base_Monotonic_Clock := Current.Base_Clock; + Base_Monotonic_Ticks := Current.Base_Ticks; + end Initialize; + +end System.OS_Primitives; |